The chairman of the Vietnam Petroleum Association says China is attempting to realize its claim of over 80 percent of the East Sea by deploying a deep-water drilling rig into Vietnamese waters.

In an interview with Thanh Nien on Tuesday, Ngo Thuong San, former general director of PetroVietnam, warned that if China successfully anchors the US$1 billion rig in Vietnam's exclusive economic zone, it will continue to expand into Vietnam’s sea territory in the future.

The tensions between the two countries have flared since the oil rig’s incursion earlier this month. China dispatched more than 80 vessels to guard the rig, leading to tense encounters with Vietnamese ships which have tried to approach it.

Ngo Thuong San: The rig wouldn't have been that grand, if it had been strictly used for oil exploration purposes--even if it drills as deep as 4,000 meters underwater. I believe that it serves both an economic and military purposes.

The video clips I've seen so far showed the rig being towed into position by military and semi-military vessels, not commercial ones. Ships hauling drilling equipment should have accompanied the rig, if the vessel's true purpose were oil exploration.

The rig’s positioning is obviously part of China’s scheme to violate and then take over sovereign Vietnamese territory. China is plotting to turn an undisputed area into a disputed one, and then seize it.

It has. But, since it doesn't hold sovereignty over the area, foreign companies never responded to its invitation to bid on the lots. The invited companies were aware that the area is situated well within sovereign Vietnamese territory.

Has the state-owned Vietnam Oil and Gas Group (PetroVietnam) ever explored the lots’ reserves?

Vietnam first explored the lots in collaboration with Russia in 1979 and PetroVietnam recently sent an exploratory vessel there. We also have records of exploration attempts by the former US-backed government in southern Vietnam in 1969. Data about the area exists but has yet to be made public.

The area has great potential, but carries many risks; that is: exploration costs could exceed the value of potential petroleum yields. For this reason, Vietnam has yet to exploit the lots and chose to put them up for bidding instead.

So, China is losing rather than gaining from the deployment of the oil rig into the Vietnamese waters?

China will not find support, either legally or morally. The move is not economically advantageous, either.

China's only ostensible goal is to implement its “U-shaped line” [an infamous map that includes over 80 percent of the East Sea] claim over the East Sea and violate Vietnam’s sea territory.

Even if it truly wanted to exploit oil in the area, it would likely be unable to do so, as the East Sea is known for big waves, lots of storms and complex hydrographical characteristics.

Despite looking grand, the Haiyang Shiyou-981 still has its limits – big things are inflexible at sea.

We used to operate in waters not far from shore under good weather conditions, but we still roughly $100 million a month per well. The cost for China to operate the rig in addition to its fleet of 60-70 guard vessels must be unimaginable.

What do we need to do to force China to move the rig?

Currently, the world has many concerns other than the East Sea issue.

The most important thing is to make the world know that these waters are part of our exclusive economic zone and that what China is doing is not designed to yield economic gains, but to seize Vietnamese territory.

Our recent moves, from the Prime Minister’s speech [that condemned China’s acts at an ASEAN summit in Myanmar last week] to the people's street demonstrations, and voices from international leaders have partly publicized China’s actions as wrong.